Rodney Payton (Modern Reader’s Guide to Dante’s Inferno, 88–89) observes that “Dante’s vocabulary is rich in words denoting water,” including “the Italian words for water, river, little river, bog, marsh, stream, pond, slough, fount, and waves, at lest. In many cases the nouns are modified by adjectives to emphasize their infernal nature (the ‘dismal little stream’ of VII, 107, for instance).”
The first simile of the poem is linked “to both the historical crossing of the Red Sea and the sacrament of baptism. In Dante’s sacramental system of salvation baptism was absolutely essential. . . . The Pilgrim must complete a true baptism at some point which will remove from him the traces of sin.” While “this ‘true’ baptism cannot occur in Hell,” still “the continual references to water and its crossing keep this very important allegory alive for the reader.”
As a result, “a system of rivers” forms “an integral part of the geography of the Inferno.” Dante and Virgil cross the Acheron, a “dismal little stream” and the Styx. Canto VII provides “particularly rich” uses of this imagery: “Plutus, when rebuked, falls like a mainmast in a storm at sea (13–15) , the hoarders and wasters are compared to waves clashing together (23–24) and the ‘dismal little stream’ flows (99-108). This last is an important point, since it is by this stream that the water, first seen in Acheron, flows into the marsh of the Styx. One should note that only rarely do the waters of Hell actually flow; the Acheron, like the Styx, resembles a lake conforming to the shape of the circle of which it is a part. Styx is, like Acheron, a major landmark denoting the end of incontinence with its sullen and wrathful sinners and its crossing marking the entry into the area of violence. In VIII, Circle 5, the Styx is actually crossed and Virgil is referred to as the ‘sea of all wisdom’ (7).”
Water rarely flows in Hell, it’s not “living water,” but stagnant, still water, ultimately the stillest water of all—ice. Dante begins his baptism by plunging into the murky death-waters of Hell, following the path of Jesus Himself who harrowed Hell, so that he can eventually rise to newness of life.